Asleep on the job.

Few technologies have evolved as rapidly as the personal computer. Today's machines are a far cry from those of even a few years ago, with the newest capable of performing basic tasks - such as printing or running a spreadsheet program - dozens of times faster than their ancestors.

However, in one respect - energy use - today's desktop computers are still dinosaurs. A typical machine uses 80 to 160 watts of power (see table), about as much as an incandescent light bulb.

Desktop Computer Energy Use

Component              Power Use (watts)

monitor                       30-70
logic board                   14-63
power supply                  15-45
hard disk drive               10-15
video or other cards          5-15
microprocessor                6
memory                        0.5-4
fan                           2
floppy disk drive             0.1-0.3

Total (average)        80-160 watts

Source: Apple computer

This may not seem like much power, but the 30 to 35 million personal computers in the United States account for an estimated 5 percent of commercial electricity use. At the current rate of growth - the fastest of any segment of the commercial market - computers' share could reach 10 percent by the year 2000, according to the U.S. Environmental Protection Agency (EPA).

To counter this trend, EPA launched in June 1992 the Energy Star Computers program, a cooperative venture between the agency and leading computer and monitor makers. The agency has convinced 18 firms - including Apple, IBM, Hewlett-Packard, and Digital Equipment Corporation - to improve the energy efficiency of their desktop equipment. Firms whose products meet Energy Star's power-saving standards can use a special logo on their products and in advertising starting in June 1993.

EPA estimates that if Energy Star computers capture two-thirds of the market by the year 2000, their use could prevent 20 million tons of carbon dioxide from pouring out of electric power plants each year - an amount equal to the output of 5 million automobiles (which happens to be the number of new cars produced in the United States each year). Also kept out of the air will be thousands of tons of nitrogen and sulfur oxide air pollutants, which lead to acid rain.

Energy Star is the most recent of several new EPA programs - such as "Green Lights," which promotes the installation of energy-saving fluorescent lights in commercial buildings - centered on cooperation with industry. While the computer industry already possessed the technical expertise to build energy-saving machines, EPA sped their design and introduction by acting as an impartial intermediary in the development of efficiency standards, according to Omar Khalifa, who directs an environmental design group at Apple Computer. Energy Star offers major energy and pollution savings because only a small fraction of the electricity powering computers now goes to machines in active use. Most computers are left on all day, even while their users take phone calls, meet, file, or go to lunch. As much as 30 to 40 percent of computers are even left running at night and on weekends.

Though it would seem a simple matter for people to turn on their machines only as needed, much as with light bulbs, human nature makes this rare. Most current machines don't turn on quickly, so many users prefer to keep them always at the ready. Even when they know they'll be away from the office for a while, many people have as much trouble remembering to turn off their computers as they do the lights.

The answer to these human failings is to develop machines that automatically drop into a low power-consumption state - in effect, go to sleep - when not in use, yet wake up immediately when needed. To bear the Energy Star logo, computers or monitors will have to use 30 watts of electricity or less when in sleep mode.

Computer makers have already developed low-power computer technology for another segment of their market - notebook-sized portable machines. Limited by the low electrical storage capacity of existing batteries, designers of portable machines have made their systems highly energy-efficient. Virtually all such machines now feature an automatic sleep mode.

Under Energy Star, computer firms are beginning to incorporate these features into their desktop systems, which are often more powerful and used for more demanding tasks. Microprocessor makers such as Intel, Advanced Micro Devices, and Cyrix (the chief competitors in the IBM-compatible chip market) have engineered into their chips the capacity to turn off all the components - disk drives, monitors, memory, network communication cards, modems - of even the most complex systems when not in use for an extended period. They are also designing them to quickly "remember" what the machine was doing when it turned itself off, shortening wake-up time.

The more-efficient machines should begin appearing in stores early this year. The computer firms that have signed up for the Energy Star program say that most of their products should meet guidelines within two years and that the added efficiency will not sacrifice performance or raise prices.

Firms that make Energy Star machines will gain access to a substantial market. EPA is working with the General Services Administration (the agency that buys or approves the purchase of most federal office equipment), the Department of Energy, and other federal agencies to encourage government purchases of the more-efficient computers. At $4 billion per year, the federal government is the world's largest purchaser of computers and software. EPA is also rounding up commitments from businesses to buy Energy Star machines whenever possible.

It shouldn't be hard to convince firms to choose the new computers, because the machines will offer immediate savings on electric bills. EPA estimates that the program should save up to $1 billion worth of electricity each year - enough to meet Vermont and New Hampshire's electric power needs for a year. And sleeping computers will emit much less heat, cutting the energy needed for cooling office buildings.

Energy-efficient computers may also ease the consciences of environmental writers who bemoan their reliance on electric power. As essayist Wendell Berry - who says he will never buy a computer - puts it: "I would hate to think that my work as a writer could not be done without a direct dependence on strip-mined coal." Power-sipping computers and other more efficient technologies may hasten the day when the economy can be powered by the sun, the wind, and other renewable sources.